1. Technical Area
Such plug valves serve as shutoff devices for liquids, gases, vapors or granular flowable materials in pipeline networks or on containers. A so-called valve plug sits rotatably in a valve housing. The inflow opening is located on one side of the valve housing and the outflow opening on the other. A bore is formed through the plug perpendicular to its center axis to allow flow of the medium. If these two openings are connected together through the plug bore, a medium can flow through. If the plug is turned by 90°, it blocks the passageway with its plug body. Plug valves may be operated manually or with a motor.
2. Prior Art
For example, from DE 24 44 716 C, a shutoff valve, especially a ball valve, is known that has a sealing ring float-mounted on each of the sides (inflow and outflow), each side of which is essentially rigid in the area of its contact surface with the plug and is provided in the area of its sides adjacent to the housing cover, on its inner wall, with a radial annular groove exposed to the pressure of the medium from the connecting port, leaving an elastically supporting arm on the housing cover. On their sides facing the housing covers, the sealing rings are each provided with a projecting sealing surface on the outside.
From DE 10 2004 043 974 A1 a ball valve seal is known wherein in a housing, a ball with a passageway is arranged as a cutoff device. The ball is connected to a switching shaft provided with a seal against the outside. The sealing rings with circumferential seals, which provide a seal on both sides but are in sliding contact with the ball, are movable axially on both sides of the ball against the force of disc springs, which in turn receive axial pressure from a retaining ring. In the case of journal-bearing balls or a rigid sealing ring, on one side of the ball only one sealing ring may be provided with a disc spring on the ball side.
In DE 85 16 162 U1 a spring-loaded ball seat for ball valves is disclosed in which the seat contact bearing a sealing ring is pressed by spring elements against the valve ball, wherein the spring elements are sealed by sealing elements against the medium flowing through the ball valve. Preferably the seat contact has a hollow cylinder that seals off the cavity accommodating the spring elements with block seals against the medium flowing through the ball valve.